Effects of high-definition transcranial direct current stimulation (HD-tDCS) on resting brain functional connectivity in schizophrenia patients with persistent auditory verbal hallucinations

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Auditory verbal hallucinations (AVH) are a challenging symptom in schizophrenia (SZ).
• Existing psychotropic treatments are often inadequate for persistent AVH.
• Neuromodulation techniques like HD-tDCS offer potential alternative treatments.

Purpose of the Study:

• To investigate the neural effects of MRI-neuronavigated HD-tDCS on brain connectivity in SZ patients with persistent AVH.
• To examine resting-state functional connectivity changes induced by active HD-tDCS compared to sham stimulation.
• To identify brain regions affected by HD-tDCS in the context of AVH.

Main Methods:

• A double-blind, randomized, parallel-arm, sham-controlled study design.
• 34 schizophrenia patients with persistent AVH received HD-tDCS (5 days, twice daily, 20-minute sessions).
• Resting-state fMRI data acquired using a 3T scanner to assess functional connectivity.

Main Results:

• Active HD-tDCS significantly altered resting-state functional connectivity compared to sham.
• Connectivity changes were observed in regions including Heschl's gyrus, temporoparietal junction, caudate nucleus, precuneus, lateral occipital cortex, and hippocampus.
• These affected regions are implicated in the pathogenesis of AVH in schizophrenia.

Conclusions:

• HD-tDCS induces measurable changes in brain functional connectivity in schizophrenia patients with AVH.
• The findings suggest HD-tDCS is a viable neuromodulation strategy for targeting brain circuits involved in AVH.
• This study provides novel fMRI evidence for the neural mechanisms of HD-tDCS in treating auditory verbal hallucinations.